Dispensing device with abrupt ejection terminating means

ABSTRACT

A piston rod extends longitudinally through a chamber of a cylinder, the latter being provided in one end wall with a dispensing nozzle. A piston surrounds and is slidable along the piston rod between a retracted position expelling matter through the nozzle, and a forward position. One or more passages are provided in the piston and/or piston rod and these passages connect opposite axial ends of the piston but are open only when the piston is in its forward position. A supply of material to be dispensed communicates with the chamber rearwardly of the piston. An arrangement is provided for assuring that material expelled from the nozzle will be expelled with at least substantially constant pressure at all times, and includes a means for abruptly terminating the ejection of the material.

[451 Aug. 13, 1974 United States Patent 1191 Roth 1 1 DISPENSING DEVICEWITH ABRUPT 3,430,816 3/1969 Nadherny et a1. 222/387 EJECTIONTERMINATING MEANS 222/387 X FOREIGN PATENTS OR APPLICATIONS [75]Inventor: Oscar Roth, Zurich, Switzerland Assignee: Involva AG, Buenzen,Switzerland 206,771 6/1955 Australia.............................222/387 16,009 9/1900 Great Britain...................... 222/387633,917 10/1927 222/387 France [22] Filed: Mar. 20, 1973 1211 pp 343,141Primary Examiner-R0bert B. Reeves Related Application Dam AssistantExaminerC. A. Marmor continuatiommpart of Sen N0 225,421, Attorney,Agent, or Fzrm-Mrchae1 S. Striker 1972. [5

Feb. 11,

7] ABSTRACT A piston rod extends longitudinally through a chamber of acylinder, the latter being provided in one end wall with a dispensingnozzle. A piston surrounds and is slidable along the piston rod betweena retracted posi- 137/522 222/380 tion expelling matter through thenozzle, and a forward position. One or more passages are provided in thepiston and/or piston rod and these passages con- [51] Int.

[58] Field of Search nect opposite axial ends of the piston but are open41/2 1 1 5 1 1 425/244 245 only when the piston 18 in 1115 forwardposition. A supply of material to be dispensed communicates with thechamber rearwardly of the piston. An arrangement is [56] ReferencesCited UNITED STATES PATENTS 7 Claims, 4 Drawing Figures provided forassuring that material expelled from the nozzle will be expelled with atleast substantially constant pressure at all times, and includes a meansfor abruptly terminating the ejection of the material.

new/22. Us

222/387 x Johnson 1,590,058 6/1926 1,716,504 6/1929 Pierce............

1,909,678 5/1933 Hi1lis..............

DISPENSING DEVICE WITH ABRUPT EJECTION TERMINATING MEANS BACKGROUND OFTHE INVENTION The present invention is a continuation-in-part of mycopending application Ser. No. 225,421, filed on Feb. ll, 1972 with thetitle DISPENSING DEVICE.

In that application I have disclosed a dispensing device, and inparticular a device for dispensing a bonding agent. Devices of this typeare used in the book-binding art and in other applications where anadhesive or a bonding agent must be dispensed and applied to a point ofuse. The bonding agent is usually accommodated in a supply vessel whichcan be heated and is supplied from this vessel via a similarly heatableconnecting conduit under pressure to a spray or dispensing arrangement.The supply vessel itself is not part of a structural unit with thespraying arrangement. When a valve is actuated the bonding agent isexpelled from the nozzle of the spraying arrangement.

Because the previously known constructions in the prior art had certaindisadvantages, including the fact that it was not possible to preciselymeter the quantity of bonding agent being dispensed during each use, Idisclosed the device set forth in my aforementioned copendingapplication wherein a cylinder was provided formed with an interiorchamber in one end wall of which there is provided a dispensing nozzle.A piston rod extends longitudinally through this chamber and issurrounded by a piston that is slidable along the piston rod between aretracted position in which it expels matter through the nozzle, and aforward position. One or more passages are provided in this pistonand/or the piston rod, and these passages connect opposite axial ends ofthe piston but are open only when the piston is in the forward position.A supply of material to be dispensed communicates with the chamberrearwardly of the piston. This construction provides for metering of thequantity of bonding agent which is dispensed during each use, and allowsthe discharge of a perfectly straight'streamof bonding agent so that theapplication of the bonding agent to a desired specific point is madeeasy. Moreover, the distances between the supply and the dispensingnozzle are small, so that heating of the material can be accomplishedreadily and without undue expenditure of energy.

However, I have found it desirable to further improve the aforementioneddispensing device, in order to assure that the stream of bonding agentor other matter which is ejected from the dispensing nozzle during eachincident of use will be ejected under a pressure that is as uniform aspossible from the beginning to the end of the ejection.

SUMMARY OF THE INVENTION It is, accordingly, a general object of thepresent invention to provide such an improved dispensing device.

More particularly it is an object of the invention to provide adispensing device which not only has the advantages set forth withrespect to the device disclosed in my aforementioned application, but inaddition makes it possible for the stream of matter which is ejectedfrom the dispensing nozzle of the device, to be ejected under a pressurewhich is at least substantially constant throughout the entire periodduring which ejection takes place.

In keeping with these objects, and others which will become apparenthereinafter, one feature of the invention resides in a dispensingdevice, particularly for applying a bonding agent, which briefly statedcomprises cylinder means having an elongated internal chamber providedwith two end walls, and dispensing nozzle means communicating with thischamber at one of the end walls. A piston rod extends longitudinallythrough the chamber and a piston surrounds and is slidable along thispiston rod between an forward position closer to and a retractedposition farther from the aforementioned one end wall. The pistondivides the chamber into two compartments located at opposite axialsides of the piston. Passage means is provided which is open andconnects the compartments when the piston is in its forward position,and is closed when the piston is in its retracted position. Supply meanscommunicates with the chamber intermediate the piston and the other ofthe end walls for supplying material to be dispensed. Pressure controlmeans is provided for assuring expulsion of material from the nozzlemeans with at least substantially constant pressure.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a vertical section throughone embodiment of a device according to the present invention;

FIG. 2 is a partly sectioned fragmentary detail view, on an enlargedscale, showing the piston of the device in FIG. 1 in its forwardposition;

FIG. 3 is a view analogous to FIG. 2 but showing the piston in itsretracted position; and

FIG. 4 is an axial section through a further embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing indetail, and referring firstly to the embodiment illustrated in FIGS. l3,it will be seen that reference numeral 1 identifies a receptacle formaterial to be dispensed, for instance a bonding agent. The receptacle 1has a cover 2 which closes it but of course is removable so thatadditional material may be admitted into it. At the lower end of thereceptacle 1 there is provided an outlet portion 3 having an openingthrough which material can be dispensed. A heating element 4for instancea Calrod (TM) unit-- extends through this opening into the interior ofthe receptacle 1 so as to heat the contents thereof if they are of thetype which require to be heated, as in the case of a bonding agent ofrequisite type. There is sufficient room for the material to flowthrough the opening about the heating element 4.

A thermally conductive member 5 is provided, serving as a support onwhich the receptacle 1 is mounted and being provided with a passage orconduit 6 which communicates with the opening of the receptacle 1 so asto receive material therefrom. A filter 7 and an additional heatingelement 8 with a thermostat 9 (all known to those skilled in the art)can be interposed in the conduit 6 or arranged in the support member forfiltering and further heating the material to be dispensed.

Mounted on the support member 5, in communication with the conduit 6thereof, is a dispensing unit having a cylinder 10 which is connectedcoaxially with a pneumatic cylinder 11. A piston 12 is displaceablyaccommodated in the cylinder 11 which latter has two openings 13 and 14for the admission and evacuation of compressed air. A piston rod 16 isrigidly connected with the piston 12, and a further piston surrounds andis slidable along the piston rod 16.

The lower end of the cylinder 10 is closed by a oneway valve 17 whichdischarges into the dispensing nozzle 18.

A set screw 19 is provided at the upper end of the cylinder 1 1,coaxially with the piston rod 16, so that it can be adjusted to therebylimit the extent to which the piston rod 16 can be axially displaced. Itwill be seen that the piston rod 16 has a conical portion 21 and acylindrical portion 24, the piston 15 surrounding the latter and beingslidable along the same between a lower forward position which is shownin FIG. 2, and an upper retracted position which is shown in FIG. 3. Asthe latter Figure also shows, an axial bore 22 in the piston 15, whichbore diverges conically in upward direction, accommodates the conicalportion 21 of the piston rod 16 when the piston 15 is in the retractedposition. In addition, the piston 15 is provided with channels 25 whichcommunicate (when the piston 15 is in the forward position shown in FIG.2) the compartments 20 and 23 into which the interior of the cylinder 10is divided by the presence of the piston 15. The channels alsocommunicate with the conical portion of the bore 22 and are blocked whenthe piston 15 is in the position shown in FIG. 3.

In operation of the novel device, material to be dispensed such as abonding agent will flow from the receptacle 1 around the heating element4 into the conduit 6, to pass through the filter 7. The thermostat 9 assures that the material will be maintained at a precisely preselectedtemperature.

From the conduit 6 the material, for instance the heated bonding agent,flows into the space 20 above the piston 15. At this time it is assumedthat the piston 12 is in its upper position by admission of compressedair into the cylinder 11 and in its forward position with respect to thepiston rod 16. This position is shown in FIGS. 1 and 2 and it will beseen that the conical portion 21 of the piston rod 16 is out of contactwith the conical portion of the bore 22 of the piston 15. Thus, thebonding agent can flow through the opening 22 and the channels 25 intothe space 23 between the nozzle 18 and the piston 15. If compressed airis now admitted above the piston 12 through the inlet 13, then thepiston 12 and thereby the piston rod 16 will be displaced downwardly (inFIG. 1). In so doing the piston rod 16 will slide in the piston 15 untilthe conical portion 21 contacts the piston 15 as shown in FIG. 3. Thiscloses thebore 22 of the piston 15 so that no further bonding agent canenter, and the piston 15 together with the piston rod 16 now continuesto move in downward direction, opening the one-way valve 17 and ejectingthe bonding agent through the nozzle 18. When the piston rod 16 issubsequently retracted again, a vacuum will develop between the piston15 and the nozzle 18, so

that a renewed charge of bonding agent can be rapidly aspirated intothis space. When the piston rod 16 is retracted, the conical portion ofthe bore 22 becomes immediately opened again.

The stroke or displacement of the piston rod 16 can be adjusted byrequisite setting of the set screw 19, and thus the quantity of bondingagent to be dispensed during the expulsion stroke of the piston 15 canbe varied at will. The more rapid the operation of piston 15, the morequickly bonding agent must be able to enter into the space between thepiston 15 and nozzle 18, and the necessary rapidity is assured by thesuction effect resulting from the movement of the piston 15 towards theupper position.

It is also possible, although not illustrated in the drawing, for thepiston rod 16 to be provided with a downwardly open axial connectingchannel which upwardly communicates with a conical portion of the bore22 when the piston 15 is in the forward position thereof. In this casethe channels 25 could be omitted from the piston 15.

Coming now to the embodiment in FIG. 4 it will be seen that the member 5and the receptacle 1 with their associated structures have been omittedfor the sake of clarity. Thus, only the actual dispensing arrangement isillustrated. In FIG. 4 the parts which are the same as or equivalent tothe parts in the embodiment of FIGS. 1-3 are identified with likereference numerals having a prime symbol.

The cylinder 11' here is connected with the cylinder 10, the latterbeing composed of an upper portion 101 and a lower portion 102 which isthreadedly connected with the upper portion 101. The piston 15' isaxially displaceably accommodated in the cylinder 10' and subdivides theinterior thereof into an upper space 20 and a lower space 23'. Piston15' is provided at its upper end with a funnel-shaped recess 103 in thewall of which there is provided a pin 104 which extends transversely ofthe recess 103. The lower end of the recess 103 communicates with aconnecting channel 25' which is split up into individual smallerchannels in the region towards the lower space 23. Screws 105 connect ahardened steel plate 106 to the lower cylinder portion 102. A nut 108connects the dispensing nozzle 18 having the outlet bore 109 to theplate 106.

A valve chamber 110 for the one-way valve 17' is also provided in thecylinder portion 102, and the valve chamber 110 has an opening 111communicating with the lower cylinder space 23, which opening 1 11 isprovided on the side facing the valve chamber 110 with a valve seat forengagement of a corresponding seating surface of the valve body 112which latter is pressed against the valve seat by the biasing spring113. A further opening 107 is provided in the steel plate 106 andcommunicates the valve chamber 110 with the bore 109 and the steel plate106 is provided on the side facing the valve chamber 1 10 with anadditional valve seat for cooperation with a corresponding furtherseating surface of the valve body 112. The latter is provided with anabutment 114 which extends through the opening 111 into the lowercylinder space 23'.

A contact face 115 is provided on the piston 15' for contact andcooperation with the abutment 114 so that, when the piston 15 moves fromits upper into its lower end position, the contact face 115 will engagethe abutment 114 as the piston approaches its lower position and willthus displace the valve body 112 downwardly towards the nozzle 18. Assoon as the sealing surface of the valve body 112 contacts the valveseat of the opening 107 which communicates the chamber 110 with the bore109, the abutment 114 will limit the further displacement of the pistonThe lower conical portion 24 of the piston rod 16 extends into therecess 103. Above the conical portion 24' the piston rod 16 is providedwith a diametrical slot 116 through which the pin 104 extends. Thelatter is thus displaceable in the slot 116 in axial direction of thepiston rod 16. Thus, when the piston rod 16 is displaced axiallyupwardly in FIG. 4, the conical portion 24 will be lifted away from therecess 103 and a space will develop between piston rod 16' and therecess 103. When the lower end 117 of the slot 116 moves into contactwith the pin 104, the piston rod 16' will take along the piston 15' inupward direction. At this time the piston 15 will be in its forwardposition so that a connection is established via the recess 103 and thechannel 25 between the upper cylinder space and the lower cylinder space23'.

In operation of this embodiment, the material to be dispensed (such asliquid glue or other bonding agent) enters through the conduit 6' intothe upper cylinder space 20 and fills the same. When the piston rod 16now moves upwardly the piston 15 initially remains in the position shownin FIG. 4. A communication develops between the upper cylinder space 20'and the lower cylinder space 23 via the recess 103 and the channel Assoon as the lower end 117 of the slot 116 moves into abutment with thepin 104, the piston rod 16' takes along the piston 15' in upwarddirection. At this time, the piston 15' is in its forward position asseen with reference to its relative displacement on the piston rod 16.During the upward movement of the piston 15', the valve body 112 engagesthe seat associated with the opening 111, closing the latter and thusclosing the valve chamber 110 with respect to the lower cylinder space23 so that a suction develops in the latter, with the result that thematerial in the upper cylinder space 20' is now drawn by this suctionthrough the channel 25' into the lower cylinder space 23.

When the piston 15 has reached its upper end position, the piston rod 16is again displaced in downward direction. As this takes place, thepiston 15 initially remains in its upper end position until the conicalportion 24' of the piston rod 16 engages the recess 103 and thus closesthe channel 25'. Now, the piston 15' is taken along in downwarddirection by the piston rod 16' and the material in the lower cylinderspace 23' is ejected through the valve chamber 110 and the opening 107and finally out of the nozzle 18'. The excess pressure which thusdevelops in the space 23 causes the valve body 112 to be displaceddownwardly against the effect of the spring 113, and as soon as thesurface 115 moves into engagement with the abutment 114, the valve body112 is displaced further downwardly and moved into sealing engagementwith the valve seat associated with the opening 107, so that the latteris suddenly closed. Appropriate dimensioning of the spring 113 on theone hand, and closing of the opening 107 via the piston 15 and the valvebody 112 on the other hand, assure that the material ejected in the formof a stream out of the nozzle 18 will be ejected under a substantiallyconstant pressure for the entire time period during which the ejectionlasts. Of course, it will be understood that the valve body 112 mustclose the opening 107 before the piston 12 in the pneumatic cylinder 11has reached its lower end position, so that the contact face of thepiston 15' can engage the abutment 114 at relatively high speed in orderto assure a sudden closing of the opening 107.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in adispensing device particularly suitable for dispensing a bonding agent,it is not intended to be limited to the details shown, since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A dispensing device, particularly for applying a bonding agent,comprising cylinder means having an elongated internal chamber; a pistonrod member extending longitudinally through said chamber; a pistonmember surrounding and slidable along said piston rod member between aforward position and a retracted position with respect thereto, saidpiston member dividing said chamber into a first and a secondcompartment located respectively at opposite axial sides of said pistonmember; supply means communicating with said first compartment forsupplying material to be dispensed thereinto; passage meanscommunicating said first and said second compartments when said pistonmember is in said forward position thereof so as to permit passage ofthe material from said first into said second compartment and preventingcommunication betwen said compartments when said piston member is insaid retracted position thereof; dispensing nozzle means; a valvechamber provided in said cylinder means intermediate said secondcompartment and said nozzle means; a first opening communicating saidvalve chamber with said second compartment and having a first sealingsurface; a second opening communicating said valve chamber with saidnozzle; a valve body accommodated in said valve chamber and having aside facing said first opening and provided with a first contactsurface; biasing means normally urging said first contact surface intosealing contact with said first sealing surface and permitting yieldabledisplacement of said valve body away from said first opening when thepressure in said second compartment exceeds the pressure in said valvechamber, whereby the material being expelled from said secondcompartment is admitted into said valve chamber to be ejected therefromthrough said nozzle means; and means for abruptly terminating theejection of the material through said nozzle means and including a firstabutment surface on one of said members, a second abutment surfaceprovided on said side and extending into the path of movement of saidfirst abutment surface, a second sealing surface surrounding said secondopening, and a second contact surface on an additional side of saidvalve body facing said second opening and sealingly engaging said secondsealing surface when said valve body is further displaced against theaction of said biasing means upon abutment of said first abutmentsurface against said second abutment surface, whereby the ejection ofthe material through said nozzle means is terminated due to the sealingengagement between said second contact surface and said second sealingsurface.

2. A device as defined in claim 1, said piston rod member having aconical end portion and said piston member having a corresponding recessreceiving said end portion, said conical end portion tightly engaging insaid recess when said piston member is in said retracted position andbeing spaced out of engagement with said recess when said piston memberis in said forward position; and an axial channel connecting said recesswith said second compartment.

3. A device as defined in claim 2; further comprising a transverselyextending pin provided in a wall bonding said recess, said piston rodmember having a diametrical longitudinally extending slot into whichsaid pin extends so as to be slidable therein axially of said piston rodmember to determine said forward position of said piston member.

4. A device as defined in claim 2, wherein said channel widens indirection toward said second compartment.

5. A device as defined in claim 1, wherein said passage means isprovided in said piston member.

6. A device as defined in claim 1; and further comprising filter meansfor filtering the material to be dis-' pensed prior to such dispensing.

7. A device as defined in claim 1; and further comprising heating meansfor heating the material to be dispensed prior to such dispensing.

1. A dispensing device, particularly for applying a bonding agent,comprising cylinder means having an elongated internal chamber; a pistonrod member extending longitudinally through said chamber; a pistonmember surrounding and slidable along said piston rod member between aforward position and a retracted position with respect thereto, saidpiston member dividing said chamber into a first and a secondcompartment located respectively at opposite axial sides of said pistonmember; supply means communicating with said first compartment forsupplying material to be dispensed thereinto; passage meanscommunicating said first and said second compartments when said pistonmember is in said forward position thereof so as to permit passage ofthe material from said first into said second compartment and preventingcommunication betwen said compartments when said piston member is insaid retracted position thereof; dispensing nozzle means; a valvechamber provided in said cylinder means intermediate said secondcompartment and said nozzle means; a first opening communicating saidvalve chamber with said second compartment and having a first sealingsurface; a second opening communicating said valve chamber with saidnozzle; a valve body accommodated in said valve chamber and having aside facing said first opening and provided with a first contactsurface; biasing means normally urging said first contact surface intosealing contact with said first sealing surface and permitting yieldabledisplacement of said valve body away from said first opening when thepressure in said second compartment exceeds the pressure in said valvechamber, whereby the material being expelled from said secondcompartment is admitted into said valve chamber to be ejected therefromthrough said nozzle means; and means for abruptly terminating theejection of the material through said nozzle means and including a firstabutment surface on one of said members, a second abutment surfaceprovided on said side and extending into the path of movement of saidfirst abutment surface, a second sealing surface surrounding said secondopening, and a second contact surface on an additional side of saidvalve body facing said second opening and sealingly engaging said secondsealing surface when said valve body is further displaced against theaction of said biasing means upon abutment of said first abutmentsurface against said second abutment surface, whereby the ejection ofthe material through said nozzle means is terminated due to the sealingengagement between said second contact surface and said second sealingsurface.
 2. A device as defined in claim 1, said piston rod memberhaving a conical end portion and said piston member having acorresponding recess receiving said end portion, said conical endportion tightly engaging in said recess when said piston member is insaid retracted position and being spaced out of engagement with saidrecess when said piston member is in said forward position; and an axialchannel connecting said recess with said second compartment.
 3. A deviceas defined in claim 2; further comprising a transversely extending pinprovided in a wall bonding said recess, said piston rod member having adiametrical longitudinally extending slot into which said pin extends soas to be slidable therein axially of said piston rod member to determinesaid forward position of said piston member.
 4. A device as defined inclaim 2, wherein said channel widens in direction toward said secondcompartment.
 5. A device as defined in claim 1, wherein said passagemeans is provided in said piston member.
 6. A device as defined in claim1; and further comprising filter means for filtEring the material to bedispensed prior to such dispensing.
 7. A device as defined in claim 1;and further comprising heating means for heating the material to bedispensed prior to such dispensing.